| The conductive polymer poly(3,4-ethylenedioxythiophene,PEDOT)is widely used in organic light-emitting diodes as a hole-transport material due to its high visible light transmittance,stable oxidation state,high electrical conductivity,and easy processing.Polymer solar cells,perovskite solar cells and other organic optoelectronics.However,the strong acidity of the disperse dopant polystyrene sulfonic acid(PSS)used therein causes the defects such as strong acidity and poor water repellency of the prepared composite(PEDOT:PSS),which seriously affects the organic photoelectric device.Stability limits its further application performance enhancements and application scope.In this paper,lignin sulfonic acid with three-dimensional network structure and sulfonic acid groups is used as a dispersing dopant,polydopamine(PDA)structure is introduced into the PEDOT system,and the amino group on the dopamine molecule is used to further consume the sulfonic acid group to achieve reduction.PEDOT aqueous dispersions are acidic and enhance PEDOT membrane water resistance.To further improve its application performance as a hole transport material in perovskite solar cells,it has certain practical value for the application of conductive polymers and high value utilization of lignin.In this paper,lignin sulfonic acid(LS)was isolated and purified by using sodium lignin sulfonate from acid process pulping waste liquid.It was used as dispersant and dopant to prepare PDA-PEDOT by chemical oxidation polymerization.: LS conductive polymer,UV-vis and infrared(FTIR)test results show that the conductive polymer was successfully prepared.The dynamic light scattering(DLS)test shows that when the mass ratio of PDA,PEDOT and LS is about 0.2:1:4,the prepared conductive polymer PDA-PEDOT:LS is uniformly dispersed in aqueous solution and the particle size is about 150.-190 nm,smaller than the conventional commercial conductive polymer PEDOT:PSS(240-260 nm);the use of cyclic voltammetry(CV)to verify the good redox activity of PDA-PEDOT:LS and the appropriate HOMO level,with PPS Compared to the HOMO level of-5.0 eV,the HOMO level of the PDA-PEDOT:LS conductive polymer is-5.2 eV.More importantly,PDA-PEDOT:LS is less acidic(pH=5.20),much lower than the commercial conductive polymer PEDOT:PSS(pH=5.20).According to the water resistance test,the water resistance of PDA-PEDOT:LS conductive polymer film is better than that of PEDOT:PSS.Based on PDA-PEDOT:LS material has a suitable highest occupied orbital(HOMO)level,weak acidity,and good water resistance.PDA-PEDOT:LS is used as a hole-transport material in perovskite solar cells.Under the premise of guaranteeing its photoelectric conversion efficiency(PCE),the PCE after 32 days of the device is still close to the initial value,while the PCE of PEDOT:PSS device is The attenuation was 58.1% of the initial value,indicating that PDA-PEDOT:LS greatly improved the stability of the device.Further,using the alkali lignin in the black liquor from the large-scale wide-alkali pulping process as raw material,high sulfonation degree and high molecular weight lignosulfonate(GSL)were prepared by grafting sulfonation technology.PDA-PEDOT:GSL polymer was prepared using GSL as a dispersant and dopant.According to the DLS test,when the mass ratio of PDA,PEDOT and GSL is about 0.2:1:9,the prepared conductive polymer PDA-PEDOT:GSL has a particle size of 100-150 nm,which is smaller than that of PEDOT:PSS(240-260).Nm).The acidity and hydrophilicity of PDA-PEDOT:GSL were improved to a certain extent relative to PEDOT:PSS.The pH of PDA-PEDOT:GSL material was as low as 5.26,the contact angle of the film was as high as 48.4,and PEDOT:PSS was 1.86 and 14.8.°.By CV test,PDA-PEDOT:GSL has good redox activity compared to HOMO level of-5.0 eV of PEDOT:PSS,and its HOMO level can reach-5.62 eV,which is more conducive to lower hole injection/extraction potential.The barrier has a certain application value for further improving the performance of the device. |
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